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API Bulk: The Final Frontier

Traditionally Postmark has focused on sending only transactional messages with the highest deliverability standards, and that’s produced a ton of loyal fans that boast we’re the best in the business! 😊

But if we can accommodate more types of messages with the same high-quality sending standards, many of our customers have made it clear that they’d prefer to use Postmark as their sole email provider.

Our mission 🛰 is to make email painless and enjoyable for product development teams, and we're in the unique position to preserve our world-class 🌎 transactional service and superior deliverability while using that experience to build the ultimate bulk sending environment in parallel ♊︎. So I’m pleased to announce that we’ve launched 🚀 brand new infrastructure that we’re calling Message Streams for managing “API bulk”, that is, similar messages sent to multiple recipients.

The loyal customers that have been testing Message Streams in our private beta are seeing consistently fast delivery that I’m over the moon 🌜about! The goal is to be more universal 🔭 about the kinds of messages Postmark can support. So far, customers have been sending mainly broadcast messages like app updates, release notes, daily digests, and event invitations. If you’d like to learn more about how we plan to support API Bulk with Message Streams, visit our Message Streams page and sign up to be notified about the public launch 🚀

Questions you might have #

Why are you doing this? #

Our goal is to fill in the gaps we see between transactional and other types of application email that need to go out to multiple recipients at once.

Traditionally we rejected all messages like this, which caused many of our customers to split their messages across multiple providers. By accepting more of these high-quality, high-engagement messages, we can eliminate the need to use multiple providers and make life easier.

Can any sender use Postmark now? #

Postmark will never be an open door to any sender. We’re still manually vetting each potential customer, chatting with them one-on-one about what they send and why. Unlike some other providers who accept almost anyone who will hand them money or free data, we’re dedicated to supporting only senders who follow and exceed best practices.

Just in case someone is especially clever at hiding their intentions, we’ve also built internal anti-abuse systems that not only help us analyze all senders’ performance but can also stop potentially spammy messages before they’re sent.

Investing in Message Streams and expanding the type of email sent through Postmark has given us even more opportunities to build and improve the systems that preserve our exceptional deliverability and high standing with receiving ISPs.

How will you maintain high deliverability for transactional email? #

Separating transactional traffic from other types of email using different sending IPs and From domains is a longstanding best practice for ensuring optimal deliverability. Different types of email have entirely different origins as well as vulnerabilities. Grouping similar types of emails together while keeping sending environments as distinct as possible helps inbox providers recognize what’s safe to place in the inbox.

We know that expanding the type of email you can send through Postmark is important to our customers. So is maintaining the industry-leading deliverability and time-to-inbox Postmark is known for. That’s why we created an entirely new sending infrastructure to support broadcast messages: one that is parallel to our transactional email infrastructure, but completely separate.

Message Streams enable Postmark users to route emails through the appropriate sending infrastructure based on how they’re sent. That means transactional and broadcast traffic never intersect in Postmark, including IP ranges. We’re proud to say that makes Postmark the only major email API provider adhering to the email traffic management standard promoted by the world’s most popular inbox providers, including Gmail.

Do you have any documentation on how to send API Bulk? #

With our /batch and /batchWithTemplates API endpoints, you can send up to 500 messages per request. You can then have up to 10 concurrent connections open, per IP, at a given time. Effectively allowing you to send up to 5,000 emails concurrently.

How do I get started? #

Postmark Message Streams and our email API for bulk sending is currently in private beta with a public launch planned for later in 2020. Sign up to get updates on Message Streams and be the first to know when we launch.

Anna Ward

Anna Ward

Head of Deliverability and professional picnicker.